Positioning Method

Abstract

Disclosed is a method of determining a position of a target node in accordance with radio signals transmitted and received between the target node and one or more reference nodes. According to the method, values of different positioning-related parameters are acquired, the positioning-related parameters being estimated from the radio signals. An error of a positioning value of the target node, the positioning value being calculated based on a value of each of different positioning-related parameters, is determined based on at least either the positioning value or a previously determined position of the target node. A weight of each of the different positioning-related parameters is determined, based on the error. The position of the target node is determined in accordance with a positioning value calculated based on the weight and on the value of each of the different positioning-related measurement parameters.

1 . A method of determining a position of a target node in accordance with radio signals transmitted and received between the target node and one or more reference nodes, the method comprising:
 acquiring values of different positioning-related parameters, the values being estimated from the radio signal;   determining an error of a positioning value of the target node, the positioning value being calculated based on a value of each of different positioning-related parameters, based on at least either the positioning value or a previously determined position of the target node;   determining a weight of each of the different positioning-related parameters, based on the error; and   determining the position of the target node in accordance with a positioning value calculated based on the weight and on the value of each of the different positioning-related parameters.   
     
     
         2 . The method according to  claim 1 , wherein
 the weight is determined based on a likelihood of the positioning value, the likelihood being calculated from the error.   
     
     
         3 . The method according to  claim 1 , wherein
 the error is determined in accordance with a theoretical value based on a previously determined position of the target node and with the positioning value.   
     
     
         4 . The method according to  claim 1 ,
 wherein for each of the different positioning-related parameters, a preliminary measurement error distribution in a positioning area of the target node is registered, and   wherein the error is determined based on the previously determined position of the target node and on the preliminary measurement error distribution.   
     
     
         5 . The method according to  claim 1 , comprising:
 selecting one positioning-related parameter from the different positioning-related parameters, based on the error;   giving a weight of 0 to positioning-related parameters other than the selected positioning-related parameter; and   determining a positioning value calculated based on the selected positioning-related parameter to be a position of the target node.   
     
     
         6 . The method according to  claim 1 , wherein
 the weight represents a mixing ratio of a positioning value calculated from each of the different positioning-related parameters, the mixing ratio being larger than 0.   
     
     
         7 . The method according to  claim 1 , wherein
 the different positioning-related parameters include at least two of an angle of arrival, a time of arrival, a time difference of arrival, and a signal strength.   
     
     
         8 . An apparatus that determines a position of the target node in accordance with radio signals transmitted and received between the target node and one or more reference nodes, the apparatus comprising:
 an arithmetic processing device; and   a storage device,   wherein the storage device stores coordinate information of the one or more reference nodes, and   wherein the arithmetic processing device carries out the processes of:   acquiring values of different positioning-related parameters, the values being estimated from the radio signal;   calculating a positioning value of the target node, based on a value of each of different positioning-related parameters and on the coordinate information of the one or more reference nodes;   determining an error of the positioning value, based on at least either the positioning value or a previously determined position of the target node;   determining a weight of each of the different positioning-related parameters, based on the error; and   determining the position of the target node in accordance with a positioning value calculated based on the weight and on the value of each of the different positioning-related parameters.